OBD Guide

B1257

Air Temperature External Sensor Circuit Short To Ground

B1257 is an OBD-II diagnostic trouble code meaning: Air Temperature External Sensor Circuit Short To Ground. Common causes: damage to the sensor wiring harness, short circuit to ground. Estimated repair cost: $17–56.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$17–56 (est.)

Symptoms

  • Incorrect outdoor temperature readings
  • Problems with climate control
  • Malfunction indicator light comes on

Causes

  • Damage to the sensor wiring harness
  • Short circuit to ground
  • Outside air temperature sensor malfunction
  • Problems in the control unit

How to Fix

  1. Check the integrity of the sensor wiring harness
  2. Measure the resistance of the temperature sensor
  3. Check circuit grounding
  4. Replace sensor if necessary
  5. Check the operation of the control unit

Related codes

FAQ

What does the B1257 code mean?

B1257 is an OBD-II diagnostic trouble code that indicates: Air Temperature External Sensor Circuit Short To Ground

What causes a B1257 error code?

The most common causes of B1257 include: Damage to the sensor wiring harness; Short circuit to ground; Outside air temperature sensor malfunction; Problems in the control unit.

How do I fix a B1257 diagnostic trouble code?

To fix B1257: Check the integrity of the sensor wiring harness. Measure the resistance of the temperature sensor. Check circuit grounding. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B1257?

Limited driving only, diagnose soon

How much does it cost to fix B1257?

The estimated repair cost for B1257 is $17–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat